// 版块颜色轮换
let color_arr = ['top-a','top-b','top-c','top-d'];
let bd_arr = ['bd-a','bd-b','bd-c','bd-d'];
let modules = document.querySelectorAll('.ns-module');
let logos = document.querySelectorAll('.font-logo');
let modules_len = modules.length;
for(let i = 0;i < modules_len;i++){
  let j = i % 4;
  modules[i].className += ' '+color_arr[j];
  logos[i].className += ' '+bd_arr[j];
}